We investigated 120 patients suspected clinically to have pulmonary aspergillosis with different clinical manifestations "aspergilloma (Subgroup A), allergic bronchopulmonary aspergillosis (Subgroup B) and invasive pulmonary aspergillosis (Subgroup C)" and correlated between their clinical and laboratory findings and endogenous specific aflatoxin production. They were subjected to isolation of Aspergillus strains, measurement of serum total IgE and specific Aspergillus IgG by ELISA and identification of aflatoxin producing Aspergillus strains using fluorescence analysis of spectroline. Aspergillus was isolated from 45 patients (37.5%). Subgroup A had a negative statistically non-significant correlation between clinical and laboratory findings as regard total IgE and for Aspergillus IgG (only haemoptysis &weight loss had significant correlation with aspergillus IgG). Subgroup B & Subgroup C had positive, statistically significant correlation &negative statistically non significant correlation respectively as regard all clinical findings and both total IgE & serum IgG. This study also showed that 6 Aspergillus strains out of 45(13.3%) produced endogenous aflatoxin. It is concluded that a significant correlation that exists between clinical and serological findings in allergic pulmonary aspergillosis. Aflatoxins may be produced in vivo by strains of Aspergillus and may result in manifestations similar to those caused by ingestion of aflatoxin in food.